Aircraft



- New. 8, 1949 ANDREWS 2,437,405

AIRCRAFT Filed Aug. 12, 1943 v 6 Sheets-Sheet l J /0 1 2/ 571 a z {Wk wen u 1i LA/ up ygaww j, 1; MM

Nov. 8, 1949 E. F. ANDREWS 2,487,405

AIRCRAFT Filed Aug. 12, 1943 6 Sheets-Sheet 2 Nov. 8, 1949 F. ANDQEWS 2,437,405

AIRCRAFT Filed Aug. 12, 1943 a Sheets-Sheet s E. F. ANDREWS Nov. 8, 1949 AIRCRAFT 6 Sheets-Sheet 4 Filed Aug. 12, 1943 Nov. 8, 1949 E. F. ANDREWS AIRCRAFT 6 Sheets-Sheet 5 Filed Aug. 12, 1943 ANDREWS Nov. 8, 1949 AIRCRAFT 6 Sheets-Sheet 6 Filed Aug. 12, 1943 Patented Nov. 8, 1949 UNITED \STATES PATENT OFFICE AIRCRAFT Edward F. Andrews, Chicago, Ill.

Application August 12, 1943, Serial No. 498,286

12 Claims.

relates to aircraft, and has for its primary object the provision of new and improved alightinggear for aircraft. This application is a continuation-in-part of application, Serial No. 148,085 filed June 14, 1937, now U. S. Patent 2,330,803, and of application, Serial No. 386,511 filed April 2, 1941, now abandoned, the latter being in turn a division of application, Serial No. 190,171 filed February 12, 1938, now U. S. Patent 2,307,654.

An object of the present invention is to provide a new and improved alighting gear which may be projected and retracted in a simple and effective manner.

Another object of the present invention is to provide an aircraft with new and improved retractable alighting gear comprising a supporting means pivotally movable about a single axis from a retracted position on one side of the axis to a projected or alighting position wherein the wheel is located at the other side of the axis and below the fuselage of an aircraft, and wherein the wheel supporting member is so located at the other side of the axis and is so inclined that the weight of the aircraft tends to move it further toward said other side about said axis.

A further obiect of the present invention is to provide a new and improved alighting gear of the character aforesaid with a closure plate adapted to close an opening in the aircraft into which the alighting gear is retractable.

A further object of the present invention it to provide a new and improved aircraft having an alighting gear comprising a pair of retractable wheels and a retractable ground contacting member to prevent the aircraft from nosing over, which alighting gear and contacting member are constructed and arranged to be simultaneously projected or retracted.

Another object of the present invention is to provide an aircraft with new and improved alighting gear and shock absorbing means.

Another object of the present invention is to provide new and improved shock absorbing means for use with retractable alighting gear, wherein the shock absorbing means is a separate unit adapted to be cooperatively associated with the alighting gear only when the alighting gear is in projected position.

A further object of the invention is to provide a unitary mechanism for performing the dual functions of shock absorption and actuation of the alighting gear between its two positions.

A further object of the present invention is to provide an aircraft with a new and improved The present invention alighting gear and shock absorber arrangement wherein the shock absorber fluid is used as the actuating means of a servo motor used in projection of the alighting gear.

Another object of the present invention is to provide an aircraft with a new and improved alighting gear wherein rapid projection of the alighting gear may be accomplished.

Another object of the present invention is to provide an aircraft with a new and improved shock absorber and a retractable alighting gear construction wherein the movement of the shock absorber mechanism to absorb the landing shock and the movement of alighting gear mechanism from one to the other of its two positions occurs about the same pivotal axis, thereby to provide an efficient construction utilizing but relatively few moving parts.

Other objects and advantages of the present invention will become apparent from the ensuing description, in the course of which reference is had to the accompanying drawings, in which:

Fig. 1 is a plan view, partly broken away, of an aircraft embodying the present invention;

Fig. 2 is a side elevational view, on a smaller scale, of the aircraft illustrated in Fig. 1;

Fig. 3 is a front elevational view of the aircraft;

Fig. 4 is a fragmentary longitudinal cross sectional view of the forward end of the aircraft;

Fig. 5 is an enlarged fragmentary detail illustratv'ng features of a modified construction of a combined alighting gear operating and shock absorbing means;

Fig. 6 is a side elevational view of a modified aircraft construction, wherein the alighting gear support has secured to it cover plates for closing wheel receiving apertures in the fuselage;

Fig. 7 is a plan View of the aircraft illustrated in Fig. 6;

Fig. 8 is a side elevational view of a power soarer havin'r embodied therein a modified form of the alighting gear of the present invention;

Fig. 9 is a fragmentary sectional view taken along the line 9-9 of Fig. 8, and illustrating details of the mounting and means for actuating the main landing wheels;

Fig. 10 is a similar view showing the wheels in retracted position;

Fig. 11 is a fragmentary perspective view, on an enlarged scale, of one wheel and illustrating the manner in which the wheels are mounted;

Fig. 12 is a fragmentary front elevational view of the aircraft showing the wheels projected for alighting;

Fig. 13 is a front elevational View of another embodiment of the present invention;

' Fig. 14 is a fragmentary perspective view, on an enlarged scale, of the aircraft shown in Fig. 13. In this view the wheels are shown in retracted position;

Fig. 15 is an enlarged fragmentary detail view illustrating features of the shock absorber construction;

Fig. 16'is a fragmentary perspective. view of'another embodiment of a unitary combined retracting and shock absorbing mechanism;

Fig. 17 is a front elevational view of another embodiment of the present invention;

Fig. 18 is a side elevational View of. the embodiment of Fig. 17, and

Fig. 19 is a fragmentary perspective view, on an enlarged scale. of the mounting andmeans for actuating the alighting gear.

Referring now to the drawings, and more particularly Figs. 1 to4, inclusive, it may be noted that the aircraft comprises a streamlined fuselage ID, a propeller l l at its forwardend, a retractable rotating wing structure l2, a fixed wing I 3', and a retractable alighting gear comprising a pair of retractable landing. wheels [4. The propeller II is preferably of the variable pitch type having associated therewith a pitch control mechanism operable by a control handle 18. Two seats H are provided foran operator and a passenger, and to provide the desired visibility, a section IS of the fuselage covering isconstructed of transparent material.

The aircraft illustrated in Figs. 1 to 4, inclusive, is of a composite type wherein the rotating Wing structure l2 is utilized during take-off and slow speed flight, and is retracted into a compartment l9 within the fuselage during high speed flight when the aircraft is sustained by the fixed wing 13 which is of small size. The details of operation of the aircraft and of the retraction and projection of the rotating wing, and of other related features, form no part of the present invention, and for a further description thereof reference may be had to my copending application, Serial No. 148,085,. filed June 14', 1937. It is believed sufficient for the purposes of the instant application to provide but a brief description of the various controls and mechanisms which arenot closely related to the subject matter being claimed in this application.

The aircraft includes a motor 2| for rotating the propeller ll through an over-running clutch 22. The motor also drives the rotating wing structure through a shaft 2.3, a clutch 24, and a generally vertically disposed shaft. section 25. The interconnection of shafts 23and 25 is effected by the clutch 24 which is controlled by a control handle 26. The over-running clutch 24 enables the shaft, 23 to be driven by the. propeller in the event the motor is not running, so that the alighting gear may be extended even though the engine fails during flight.

The compartment I9 may'be closed by'a slidably mounted panel 21-, the position of" which is controlled by a spring 28 and a cranking mechanism 29 connected to the panel by a cable 3| Thus, when the rotating wing structure is retracted into its compartment I9, the compartment may 'besclosed'by thepanel 27.

The rotating wing structure. I2 includes a pair of, extensible rotating wings 32. adapted to be wound upon drums 33', after. which the. structure is movable downwardly into the compart-v ment IS. The retraction and extension of the rotating wings 32 is controlled by the rotation of a hand Wheel 34. After the wings have been retracted the structure may be withdrawn into the compartment I 9, in a manner to be described shortly, provided the structure has been properly positioned in a fore and aft position by moving a lever 35 rearwardly. When this is done, a lever 36 is forced against cams 37 rotating with the rotating wing structure, thereby to arrest the drums 33- in the. proper fore andaft relation for retraction into the compartment l9.

The rotating Wing structure is so constructed and arranged that its axis of rotation may be inclined, thereby to provide a roll and pitch control for the aircraft. This control is effected by a control handle 38 operatively connected to the rotating wing structure. The control handle 33 is also utilized to control the high speed flight of the aircraft after the rotating wing structure has been retracted. The high speed flight is con trolled through cables 39 controlling thev elevators and cables ll controlling the ailerons of the aircraft, in a manner disclosed in my copending application.

The projection of the rotatingwing and also of the alighting gear is effected hydraulically, wh ereas the retraction of the rotating wing is effected by gravity and the retractionof the alighting gear is effected by resilient means. The necessary hydraulic pressure is provided by a pump 42 driven through the shaft 23. The pump has associated with it a suitable reservoir 43 for the hydraulic fluid, which is preferably oil. The inlet of the pump is connected to the reservoir by a conduit The outlet is connected to the reservoir through an automatically operating pressure relllf valve 35, and also through a valve 46 manually operable to open and closed positions by a control handle 41.

Oil under pressure is supplied to the rotating wing and alighting gear projecting apparatus through a four-position valve 48 which is operable into its various positions manually, as by. a control handle 49. In one positionv of the valve 48 the valve is closed. In asecond position the outlet of the pump is connected to servo motor means for projecting boththe rotating wing and alighting gear structures. In a third position the outlet of the pump is connected to the rotating wing projecting servo motor, whereas in the fourth position the outlet of the pump is connectedto the alighting gear projecting servo motor. When the outlet of the pump is thus connected to one or both servo motors the positionof valve 46 determines whether or not the devices are to be projected or retracted. If the Valve 48 is closed, then the devices are projected, whereas if valve 46 is open and thus connects the outlet of the pump directly to the reservoir, then the devices will be retracted, provided, of course, that they are in their projected positions. The relief valve is. set for asufiiciently high pressure to ensure projection of the rotating wing, structure and of the alighting gear when the valve 46 is closed, but permits a restricted flow of oil to the reservoir under certain conditions to be described hereinafter..

The rotating wing structure is projected when oil under pressure is supplied to cylinders SI (of which there are four, although but two are shown). The lower ends of the. cylinders 5| communicate with headers 52 connected. by a conduit 53.t0 the .valve. 48.

The. present invention pertains particularly to the construction and arrangement of the retractable alighting gear. The alighting gear includes the previously referred to wheels M which are mounted on pivotally movable supports 54 which terminate in yoke-like portions 55 partially surrounding the wheels. The supports are each movable about a single transverse axis inclined downwardly and inwardly, as best shown in Figs. 3 and 4. The upper ends of the supports 54 terminate in bearing members 56 rotatably movable about shafts 51. The shafts may be attached to the fuselage in any suitable manner, as by the spaced apart bearing blocks 58, when the wheels are to be retracted into the fuselage. If desired, the shafts could be secured to the wings or nacelles if the wheels should be retracted into the latter.

In accordance with one of the features of the present invention, the alighting gear construction is such that in retracted position the wheels are located to oneside of the axis, whereas in alighting position the wheels and their supports are located at the other side of the axis and the supports are so inclined that the weight of the aircraft tends to move them further toward said other side about the axis. Accordingly, the alighting gear is securely held in alighting position when the aircraft lands.

In accordance with another feature of the present invention, the actuation of the alighting gear between its two positions is performed by a unitary mechanism performing also the function of a shock absorber mechanism, In addition, the construction is such that the movement of the shock absorber mechanism to absorb the landing shock and the movement of the alighting gear mechanism between its two positions occur about the same pivotal axis.

Each of the alighting gear supports 54 is projected by a servo motor mechanism, indicated generally by the reference character 6|, which is best illustrated in Fig. 4, to which reference is now had. It should be understood that there are two of these mechanisms, although but one has been illustrated. The mechanism includes a cylinder 62 within which is slidably mounted a piston (not shown) connected by a piston rod 64 to the bearing member 56. The connection between the piston rod '54 and bearing member is pivotal, and the cylinder 62 is pivotally attached to the fuselage, as through a block 65. It should be understood. however, that other constructions may be utilized to interconnect the piston and arm. For instaneathe cylinder may be fixed and the piston be connected to the arm by a pin and slot connection (the slot being formed in the piston rod) or by a connecting rod pivotally attached to the piston and arm.

The projection of the landing gear into alighting position is accomplished by operating control handle 41 to close the bypass valve 46, and operating control 49 to position valve 48 to connect the outlet of pump 42 to the cylinders 62 through conduits 66 of restricted size enabling oil to be supplied to and flow from the cylinders but relatively slowly. When the controls are so operated, oil is forced by the pump into the cylinders, thereby to move the pistons therein toward the right as viewed in Fig. 4. The pistons moving to the right compress springs 67 located between the pistons and the right ends of the cylinders, and move the landing wheel supports 54 clockwise about shafts 51 until they reach their alighting positions. The overpressure relief valve 45 is set so that, or the pump may be 6 designed to produce a pressure such that, the springs 61 are not fully compressed. Then when the aircraft lands, the force of impact results in the sudden compression of the springs 61 by the movements of the pistons. The pump thereafter slowly supplies additional oil into the cylinders 62 through the restricted conduits 66, but not until the springs have been further compressed substantially solely by the force of the impact. After the force of impact decreases, the springs 61 expand forcing the piston to the left to return the oil back through the conduits 66 and through the overpressure relief valve into the reservoir. The restricted outflow of oil from the cylinders provides a good shock absorbing action.

The alighting gear is returned to its retracted position by the spring 6! located within the cylinder 62 and bearing against the piston (not shown) and the opposite end of the cylinder. The spring is compressed during the projection of the alighting gear, so that when the valve 46 is opened and Valve 48 connects the cylinder 6| to the reservoir, the spring 61 moves the piston and thereby retracts the alighting gear.

Reviewing the actuation and shock absorption it may be noted these are performed by a unitary mechanism and that the retraction and projection movements and also the movements in shock absorption occur about the same pivotal axis, namely, the shaft 51 about which the landing wheel supports 54 move. A simplified and rugged construction is thus provided.

The alighting gear is preferably so constructed and arranged that the wheels I4 are retracted into the fuselage, preferably behind the passenger seats II as indicated in Figs. 1 and 4, although, as previously indicated, the wheels could be retracted into other parts of the aircraft. In retracted position the wheels thus are located substantially centrally of the fuselage and to the rear of the Wings 13, whereas in projected position they are located relatively far apart and below the front of the wings. In other words, the wheels and wheel supports are swung forwardly, outwardly, and downwardly to a landing position wherein the shock of impact with the ground aids in holding the alighting gear in position. Undue movement of the alighting gear on landing is prevented by the shock absorber mechanism, including the springs 67 within the cylinders 62.

' If it is desired to project the alighting gear rapidly the cylinder may be supplied with oil rapidly and the outflow may be retarded and the cylinder constructed with two springs, one operating primarily in retraction and the other in shock absorption. The rapid inflow and retarded outflow may be. obtained by placing a valve in the connection between the pump and cylinder, as illustrated in Fig. 5. In this figure the cylinder 68 is supplied with oil through a valve 69 lightly biased to a closed position by a spring lit acting against one of a pair of spaced apart webs H in a detachable valve casing 12 and a Washer secured to the valve stem I3. Oil is supplied to the valve casing through a' conduit 14 capable of supplying oil to the cylinder at a substantial rate. The flow of oil from the cylinder is restricted by the valve so that oil can flow only through apertures 15 in the valve, thus insuring the slow dissipation of the energy of the landing shock stored in the spring so that the aircraft does not bounce into the air. Thus oil is supplied to the cylinder more rapidly than it can. flow from it, because valve I59 is fully open.

when oil" is supplied and closed during return flow.

The alighting gear is actuated by a piston rod 76 connected to the piston TI. The piston is moved to the right, as viewed in Fig. 5, by the oil and against a spring l8 adapted to return the piston to its original position in the retraction of the alighting gear, i. e., when valve it is opened. A heavier and shorter spring I9 is provided to absorb the shock of impact upon landing when thewheels are in alighting position. The force of the impact compresses the springs I8 and 19 and oil flows into the cylinder to keep it filled. When the force of impact decreases, the springs movethe piston to the left, slowly forcing the oil back to the reservoir through openings 15 in the now closed valve 69 and the relief valve 45.

The use of two springs within the cylinder, as shown in Fig. 5, is preferable to the use of a single spring, and it is contemplated that the construction of Figs. 1 to i could be modified in this respect.

In the modification of the invention illustrated in Figs. 6 and '7, the landing wheels I4 are so constructed and arranged that the wheels are located somewhat further forwardly of the air craft in retracted position. The wheels are mounted on pivotally movable supports 8| pivotally secured to the aircraft, preferably the fuselage, and braced relative to the aircraft when in projected position by braces 82. The aircraft is provided with recesses for the supports Ill and braces 82, and recesses 83- are also provided for the wheels I l. Cover plates 8-4 are secured to the wheel supports 8 I, and these are so positioned relative to the wheel supports, and the axes of pivotal movement of the wheel supports are so located and arranged, that when the wheels are in retracted position the cover plates 85 close the recesses 83, whereas in alighting position the cover plates 8 are located above the ground so that the wheels may perform their intended function. It should be noted that the instant construction requires no relative movement between the cover plates and the wheel supports s in order for the plates. to close the recesses in retracted position and to clear the ground in alighting position.

In Figs. 8 to 12, inclusive, there is illustrated another embodiment of the present invention applied, for illustrative purposes, to a power soarer, certain features of which are disclosed and in my copending application, Serial No. filed April 2, 1941, which is a division of my application, Serial No. 190,171, filed February 12, 1938.

The aircraft comprises a fuselage IllIl, the front part of which is enlarged to provide a chamber IIII for the accommodation of two passengers who may sit side by side. The upper portion I02 of the chamber IIlI may be in the form of a transparent housing in order to provide visibility for the passengers in all directions. The fuselage is provided with elevators IE3 and with a rudder both of which may be actuated in the usual.

manner. The rudder its provides bearings for a small wheel W5 which projects below the rudder andv the adjacent portion of the fuselage. The wheel Hi5. being mounted on the rudder I94, enables the machine to be steered on the ground by means of the rudder controls. Adjacent the nose of the fuselage the aircraft is provided with a ground contacting means, preferably in the form of a skid I96. This skid is capable of being drawn up into a slot: IIll (see Fig. 12) which under surface of the noses Whenretracted into the slot the skid fills-the slot so as to complete the smooth outer form of the fuselage. The skid is pivotally connected to the fuselage at I08 and also to a rod I09 extending outside of a dash pot I I0 which in turn is pivotally mounted within the fuselage. A spring I I I within the dash pot forces the rod Hi9 and the skid I68 downwardly to' the lowerlimit of movement of the rod. The dash pot strongly opposes sudden movements of the skid I636, while gradual movements of the skid from its position within its slot downwardly are permitted under the influence of the spring III. and gradual upward movements from its operating position are permitted when sufficient force is applied to overcome the spring II I.

The nose skid is-retracted into the fuselage by means of a crank H2 adapted to rotate a drum I I3 which is operatively connected to the nose skid through a cable H4. The drum is affixed to a shaft IIE connected to the crank through bevel gearing I I6. When the crank is rotated in one direction the cable I I4 is wound on the drum and the skid I66 drawri upwardly into its slot against the action of spring I I I. When the crank is rotated in the opposite direction the. cable is unwound from the drum and the spring III forces the skid downwardly. It will likewise be understood that when the skid. I [56 comes into forcible contact with the ground in landing, the dash pot H0 prevents the rapid upward movement thereof so. that it takes the impact, which is thus in part communicated to the fuselage-and in part dissipated in heat in the dash pot III]. The spring II I tends to maintain the skid fully extended. A very effective braking action can be had by operating the elevator I03 so as to raise the tail and force the skidv firmly against the ground. The location of the skid near the-nose of the fuselage effectively prevents the aircraft from nosing over despite the relatively rearward position of the additional members of the alighting: gear.

The aircraft is provided with a retractable alighting gear constructed in accordance with the principles of the present invention. The alighting. gear. includes the two wheels II! which are pivotally mounted on stu-b axles I I8. These axles are. carried by yokes II9 (see particularly Fig. 11, illustrating one of two identical wheel supports) which are pivotally mounted by means of bushings I ZO and I2I on suitable longitudinal frame. members I22 of the fuselage frame. The frame members I22 are preferably located at the lower corners of the fuselage, as shown in Figs. 9 and. 10, and the lower wall of the fuselage is provided. with openings I23 through which the wheels II! and the yokes II9 are adapted to pass into the interior of the fuselage, that is, from the position shown in Fig. 9 to that shownin Fig. 10.

The yokes II9 carry closure plates I24, which are adapted to close the openings I23 when the landing wheels are moved into their retracted positions, as shownin Fig. 10. Whenthe wheels are projected from that position into the alighting position shown in Fig. 9 for the purpose of. supporting the aircraft on the ground, the closure plates I24 serve as mud guards to prevent mud or water from being splashed over the fuselage.

When the wheels are in alighting position, pairs of abutments I25 and I26'formed integrallywith bushings I20 and I2I, respectively, engage. re) silient dampingpads I21, composed, for example,

of shock absorbing rubber, which may be suitably carried by abutments I28 upon elements of the framework of the fuselage, as shown in Fig. 11, so that components of the force applied to the wheels by contact with the ground may displace the wheels upwardly from their position shown in Fig. 9 only a limited amount as determined by the compression of the resilient damping pads. It will be understood that the pads I21 are shown only by way of example, and that any suitable damping means may be substituted therefor.

. The landing wheels II1 are actuated between their retracted and projected positions in unison by means of chains I29 extending around sprockets I30 integral with or rigidly secured to the bushings I20 of yokes I I9. The chains are operatively engaged by a sprocket wheel I3I rigidly carried by the previously mentioned shaft H5 which, it may be remembered, is rotated to effect retraction and projection of the nose skid I06. It will thus be seen that when the nose skid I06 is released to move downwardly the wheels Il1 are moved from the retracted position in which they are shown in Fig. 10 to the alighting position in which they are shown in Fig. 9, and that when the wheels are retracted the skid is also retracted into its associated slot.

The wheels Il1 are located somewhat in front of the center of gravity of the machine when fully loaded, so that when the wheels are projected the wheel I05 will remain in contact with the ground although it will carry only a very light load. Under these circumstances the skid I06 will substantially clear the ground. The position of the wheels H1 is, of course, sufficiently close to the center of gravity so that the elevator I03 will control the angle of the aircraft with only a small relative air flow over its surface.

In the embodiment of the invention illustrated in Figs. 13, 14 and 15, the fuselage of the airplane is indicated generally by the reference character I40. The front part of the fuselage is constructed to provide a compartment for the accommodation of a pilot and a passenger or copilot, for whom two seats I4I are provided. The upper portion of the compartment may comprise a transparent housing member I42 providing visibility for the passengers in all directions. The fuselage may be provided with elevators and a rudder and also a rudder wheel 26, as described in conjunction with the last described embodiment, so that the machine may be steered on the ground by means of the rudder controls.

The airplane is provided with ground contacting means near the nose of the fuselage, which means may take the form of a wheel I43 rotatably carried by a wheel yoke I44 at the end of a pivotally movable wheel supporting member I45. The member I45 is pivotally movable as about a pivot pin I46 suitably secured to the fuselage. The wheel and wheel support are adapted to be drawn up into a slot I41 in the fuselage, which is provided with an enlarged rear portion I48 to receive the wheel. In retracted position the wheel support I45 closes the slot I41 and the wheel fills up the rear portion I48 to provide a smooth outer form for the fuselage except for the small projecting portion of the wheel.

The wheel support I45 is projected and retracted, and held in retracted position by a linkage mechanism including a link I49 pivotally connected to the wheel support I45 and to an arm I50 rigidly mounted on a shaft I5I mounted for rotation about an axis disposed transversely of the fuselage. It will be noted that when the shaft is rotated in a clockwise direction as viewed in Fig. 14, the wheel and wheel support will be projected from the fuselage. When fully extended the arm I and link I49 have their common pivot located slightly forward of the two other axes of the linkage system, i. e., it is over center with respect to the latter so that any upward force will tend to move the linkage forwardly, which tendency is effectively prevented by a stop arrangement consisting of a projection I52 on arm I50 and a pin I53 on link I49.

The nose wheel and its supporting mechanism are actuated by a chain belt drive including a chain I54, a sprocket I55 on'shaft l5I, and a sprocket I56 on a shaft 151 rotatably supported in the fuselage near the seats MI. The shaft I 51 also carries a sprocket wheel I58 and a hand wheel I59. The sprocket wheel I58 is operatively connected by a chain I60 to a sprocket I6I rotatably mounted on a shaft I62 which may be suitably located transversely of the fuselage at a low position therein. The sprocket I 6| is resiliently connected to the shaft I62 for a purpose which will appear more fully hereinafter, as by means of a spring I6I' having one end secured to the shaft and the other to the sprocket. The resilient connection provides a torque transmitting connection providing relative movement between the members to which it is connected when the torque exceeds a predetermined value. If desired, other means, such as a slip clutch, could be utilized for this purpose. The shaft I62 has secured thereto a pair of opposed bevel gears I63, only one of which is shown in Fig. 14. These bevel gears mesh with bevel gears I64, each of which is rigidly mounted on a shaft I65. The ,shafts I65 (of which only one is shown) are mounted for rotation in a substantially, horizontal position in suitable bearings (not shown), so that they extend rearwardly and outwardly relative to the bevel gears I64 as best illustrated in Fig. 14.

The alighting wheels I66 are mounted on supporting members I61 secured to and rotating with the shafts I65, so that the wheels may be moved between retracted and extended positions. The Wheels are mounted on stub axles I68 secured to the free ends of supports I61. The stub axles are so disposed that they extend substantially horizontally and rearwardly when the wheels are in their retracted positions, as shown in full lines in Fig. 14, and extend horizontally and transversely in their extended positions as shown in dotted lines in the same figure. The construction is preferably such that in retracted position the wheels are located immediately to the rear of the seats I4I within the fuselage. The wheels enter the fuselage through openings I69 in the bottom of the fuselage, and these openings are adapted to be closed by closure plates I10 when the wheels are in their retracted position. The closure plates may be suitably secured to the wheel supporting members I61, as by rods I1I When the wheels are in their extended positions the wheel supports come into operative engagement with shock absorber mechanisms. The shock absorber mechanisms include plungers I12 adapted to abut against shoulders I13 on the wheel supports I61 so that the. wheels support the fuselage with a certain degree of resilience. The shock absorber mechanisms include also cylinders I14 containing springs and hydraulic shock absorbing means and which may be suitably secured to the interior of the fuselage.

The retractable mechanisms are. maintained in their retracted and projected positions by a detent mechanism including anotched diskl lzt secured to the hand operated shaft t! and a cooperating detent HG spring biased toward the disk and adapted manually to be lifted out of the notch.

Assuming that the retractable mechanisms are in their retracted positions as shownv in full lines in Fig. 14, then if it is desired to project them it is necessary first only torreiease the detent disk H5 by pulling the detent HG upwardly against the bias of the spring associated with it. When this is done the alighting wheels (56 and the nose wheel M3 drop downwardly from their retracted position under the influence of gravity. Their projection is completed by rotation of the hand wheel 159, and when they have been projected the detent disk is again held by the detent to hold the wheels in projected position. When it is desired to retract the Wheels the detent Ht is elevated and the hand wheel operated in the appropriate direction to elevate the wheels, When the wheels have retracted the detent is released and the Wheels are accordingly again held in position by the detent mechanism.

The resilient connection between the sprocket NH and shaft it2- utilized to actuate the alighting wheels is sumciently strong to impart the requisite torque to actuate and to hold. the alighting wheels in. their various positions. However, when the wheels are in their projected positions in landing, then upon contact with the ground the wheels and their supports are moved in a clockwise direction about the axis plunger of the shock absorber mechanism. Under these conditions the spring 161 yields to enable the shock absorber mechanism properly to function and also prevents damage to the positioning detent mechanism. It may be noted that in this construction, as in the others previously described, the landing wheels and their supports move from one side to the other of the axes of their movement, with the result that the weight of the plane tends to. hold the aiightinggear in retracted position, both during landing and at rest. The arrangement of Figs. 13, 14, and 15 is particularly advantageous in a construction wherein the wing includes a wing. bar H! extending through the fuselage behind the seats Hi l and just above the wheels 5.66 in their retracted positions. The wings also include ribs H8 mounted in spaced relation along the length of the wing bar ill. The ribs. are reinforced by braces H9.

The wheel supports and mounting illustrated in Figs. l3,v 1.4, and 15, lend themselves to actua tion by a unitary mechanism utilized also to perform the function of shock absorption. A construction of this character is shown in Fig. 16, to which reference is now had. The wheel support it] for one of the wheels is rigidly secured to a horizontal shaft inclined inwardly and forwardly of the fuselage. It is adapted to be rotated in opposite directions by a power shaft i353. connected, if desired, to a similar shaft associated with. the other landing wheel (not shown). If desired, the power shafts 180 could be driven by individual motors.

The rotation of power shaft I is transmitted to shaft it? through a slidable coupling l8l, an axially movable shaft I82 journaled for rotation in bearings I83, a worm gear I 84 rigidly secured to shaft I82 and a worm wheel i852 secured to shaft I65. The. worm gear and worm wheel are Hi5 against the 5'- irreversible, is a, rotation of the gear efieots rotation of the worm wheel "but rotation of the latter tends. only to;v produce axial movement of the worm. gear. Duringextension! of the alighte ing gear axial. movement. of shaft 1.8.2 and gear 583; is prevented by a shock absorber spring i 85 mounted within an oil containing cylinder I8 1 and bearing against. the end of the cylinder and a piston I88 at. the adjacent end of shaft 1 8.2. The spring normal ly maintains the; worm gear against the left. bearing I83. The piston ispro- :vided with a valve (not shown) restricting flow of oil: from one side to the other of thepistonas it movestotheleft, but permitting relatively free movement of oil whenthe piston moves to the right, as it doesduring compression of the spring. During retractionthe shaft I8 2 is prevented from movingaxially by one of thebearings I83.

Retrac-tion and extension of the ali'ghtinggear and shock absorption are all effected by the mechanism. 'I-o retract orextend' the mechanism itis necessary' only to rotate shaft in one directi'onor the other. The worm gear l'84 is, prevented frommoving axially by the spring 186 during; extension and by one of bearings I83 during retraction so that rotation of shaft [83. produces rotation of worm wheel I85 and movement of the landing-wheel. The irreversible drive of the worm gear and wheel prevents, the landingwheel and its sup-port. from rotating the gear res and the power shaft so that the, landing wheel stays in the position into which it. is operated. On landing the force of the impact, turns, the wheel support ['61 and wormwheel, further in the extending direction. (clockwise, as viewed in Fig. 16) whereby worm gear. L84 and. shaft 1-83 are moved to the right. to compress. spring. 186. This movement is Substantially unrestricted beause. of, the previously mentioned valve em, bodied in the piston. When the force of the impac decreases. the spring forces. the piston, and also. the. shaf 182, etc.,. back slowly until they all. resume heir normal, extended positions. provided, of course, subsequent shocks.- are: not transmitted before such return is. effected. This construction thus. also; has. a. unitary mechanism for effecting retraction and extensi n. and shock. absorp ion and themovements. for these all take place. ab ut. a s ngle axis. namely-l defined by Shaft Hi5.

The embodiment. of the invention. illustrated in Figs. 17,, 18.,.and.19i, is similar to. that of 6 and- T, except that the; wheels and: supports. are adapt d: to. be moved. farther forward, thereby to provide more learance between the. closure plate and ground; when. the alisliting e r is. i aIightmsQQsitioR. linaddition, the closure plate is adapted to. close. a, recess. in the fuselage for the; wheel and supporting structure; Referring now more particularly to the. drawings, to may: be noted: that. the fuselage t9!) is provided with an elongated recess 91: at its. side, which recess; is enlarged at its. rear end as shown by referencecharacter 1-92, to receive the Wheel; While the details of but. one recess have been shown, it should be understood that thereare two suchrecesses, one at each side of the fuselage for the alighting wheelsand supports at the respective sides; lZhe alighting wheels [93 are rotatably carried at the. free ends. of pivotally movablev supports. 1:94., the opposite. ends of which extend at. substantially right. angles to. the. main longitudinal portions. toiprovidea shaft portions til-i (see Fig. 18).. The shaft portions. I95.- are rotairably 13 supported in bearing blocks I96 secured to the fuselage and actuating arms I91 are secured to the shaft portions [95 intermediate the bearing blocks, so that a mechanism I98 like that described heretofore in connection with the first embodiment of the invention may be utilized to project and to retract the alighting gear. A closure plate I99 is secured to each wheel support, and it has a configuration such as to close the recess ISL-i9? when the alighting gear is in its retracted position. In this embodiment, as in the others, the closure. plates are located above ground in the alighting position by movement of the wheel supports over center to the opposite sides of the axes of pivotal movement of the supports occupied by them in actuated position.

From the foregoing description of various embodiments of the present invention, it may be noted that the principles thereof may be embodied in structures of various forms; It should be understood, therefore, that the details of the specifically described embodiments are not intended to be limitative of the invention except in so far as set forth in the accompanying claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an aircraft having landing gear movable between retracted and alighting positions, the combination including, a combined ianding gear actuating and shock absorber mechanism including relatively movable members and spring means opposing relative movement in one direction between said members, means connecting one of said members to the landing gear in a manner providing relative movement between the landing gear and said one member, and means securing the other member to the aircraft.

2. In an aircraft having landing gear movable between retracted and alighting positions, the combination including, a combined landing gear actuating and shock absorber mechanism including relatively movable members, means for operatively connecting one of said members to the landing gear, means connecting the other member to the aircraft, means for effecting relative movement between said members to retract and extend the landing gear between its two positions, means permitting relative movement between said members under landing impact, and shock absorber means including compression spring means effective during said last mentioned relative movement.

3. In an aircraft having landing gear movable between retracted and alighting positions and for shock absorption, the combination including, a combined landing gear actuating and shock absorber mechanism including relatively movable members and spring means opposing relative movement in one direction between said members, means movably securing one of said members to the landing gear, and means securing the other member to the aircraft.

4. In an aircraft having landing gear movable about a single axis between retracted and alighting positions, the combination including, a combined landing gear actuating and shock absorber mechanism including a cylinder, a piston, spring means between saidcylinder and piston, and hydraulic means for moving said piston, means securing said piston to the landing gear, and means securing said cylinder to the aircraft.

5. In an aircraft having landing gear pivotally movable about a single axis between retracted and alighting positions, the combination including, a fluid actuated mechanism for effecting relative movement of said landing gear between its two positions, said mechanism including a cylinder pivotally secured to the aircraft and a piston pivotally secured to the landing gear, means for supplying fluid to the cylinder to effect relative movement between the cylinder and piston, and means for restricting the flow of fluid from said cylinder whereby the mechanism acts as a shock absorber during landing.

6. In an aircraft having landing gear movable between retracted and alighting positions, the combination including, a fluid actuated combined landing gear actuating and shock absorber mechanism including members movable relatively by a fluid, means operatively connecting one of said members to the landing gear, means operatively connecting the other member to the aircraft, resilient means opposing movement of said members in a direction to effect extension of the landing gear and effective to retract said landing gear, means for supplying fluid to said mechanism to effect movement of said landing gear into its alighting position, and means permitting restricted flow of fluid for absorbing landing shock.

'7. In an aircraft having landing gear pivotally movable between retracted and alighting positions, the combination including, a fluid actuated mechanism for effecting movement of said landing gear between its two positions, gsaid mechanism including relatively movable members secured to the aircraft and to the landing gear, spring means biasing said members for movement in landing gear retracting direction, means for supplying fluid to the fluid actuated mechanism to effect relative movement between said members in opposition to said biasing means and for movement in landing gear extending direction, said movable members moving further in said extending direction under landing im-, pact, and means for restricting the flow of fluid from said mechanism whereby the mechanism acts as a shock absorber during landing.

8. In an aircraft, landing gear pivot-ally movable about a single axis between retracted and alighting positions, a combined landing gear actuating and shock absorbing mechanism including a cylinder, a piston, springmeans between said cylinder and piston adapted to be compressed to absorb the shock of landing impact, and hydraulic means for moving said piston and also compressing said spring means, means pivotally securing said piston to said landing gear at a point removed from said'axis, and means pivotally securing said cylinder to said aircraft.

9. In an aircraft, landing gear pivotally movable about an axis between retracted and alighting positions and having a portion removed from said axis, a combined landing gear actuating and shock absorbing mechanism including relatively movable members, means for pivotally connecting one of said members to said portion of the landing gear, means pivotally connecting the other member to the aircraft, hydraulic means for effecting relative movement between said members pivotally to move said landing gear to move it from its retracted to its alighting position, said relativelymovable members being movable under landing impact. and shock absorber means including compression spring means compressible by said hydraulic means and 'upon ilanding impact, said spring means abeing operatively connected :to said relatively movable members and =eflfective to return :said landing gear to its retracted position.

10. Juan aircraft, landing gearmovable pivotally about -a :single axis lbetween retracted and alighting positions, -said gear including .a wheel supporting member havingportions extending in opposite directions -fromn-said axis and movable about said axis, a wheel secured in one of said portions, landing gear actuating mechanism lincluding relatively movable members, means pivotally-connecting-one-of said members to the other portion of saidlanding wheelsupporting member, means pivotally connecting the other member to the aircraft, and means including shock absorber mechanism for effecting relative movement between said members to move the landing wheel supporting member about said axis between its said two positions, said shock absorber mechanism including hydraulic actuating means 'for moving said relative'lymovable members and a spring compressed thereby, said spring being also compressible further as a result of the impact of landing.

'11. man aircraft having landing gear pivotally movable about a single axis between retracted and alighting positions, the combination including, a fluid actuated mechanism for effecting relative movement of said landing gear between its two positions, said mechanism including relatively movable elements comprised of a piston and cylinder combinations, one of said elements being pivotally secured to the aircraft and the other -'of said elements being pivotally secured to the landing gear, means for supplying fluid to the cylinder to effect relative 'movement'between the cylinder and piston, and means for restricting the flow of fluid from 16 said cylinder-whereby the mechanism acts as a shock absorber during landing.

1-2. In an aircraft having landing; gear movable about a sing'le axis betweenretracted and alighting position, the combination including acombined landing gear actuating and shock absorbermechanism including relatively movable elements comprised of a piston and cylinder rcombination, springmeans between said cylinder and :piston, hydraulic means for moving said :piston, oneof said elementsibeing secured to the aircraft :and the other of said elements being secured to the-landing gear.

EDWARD \F. ANDREWS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED vSTATES PATENTS Number Name Date 1,442,155 Klemin Jan. 16, 1923 1,747,563 Yonkese Feb. 18, 1930 1,757,687 Silva, Jr. May 6, 1930 1,768,696 Laddon July 1, 1930 11,885,392 Tuten Nov. 1, 1932 2,090,036 Frise Aug. 17, 1937 2,091,509 Kramer Aug. 31, 1937 2,180,462 De Seversky Nov. 21, 1939 FOREIGN PATENTS Number Country Date 338,502 Italy Mar. 31, 1936 112,593 Great Britain vJune 29, 1934 469,965 Germany June 4, 1928 556,531 France Apr. 16, 1923 584,330 France Nov. 18, 1924 632,964 Germany July 6, 1936 698,049 Germany .Oct. 31, 1940 Certificate of Correction Patent No. 2,487,405 November 8, 1949 EDWARD F. ANDREWS It is hereby certified that errors appear in the printed specification of the above numbered patent requlring correction as follows:

Column 15, line 33, for combinations read combination; column 16, line 35,

of references cited, for the patent number f 469,965 read 460,965

end that the said Letters Patent should be read with these coirections therein that the same may conform to the record of the case in the Patent Ofiice.

Signedend sealed this 28th day'of March, A. D. 1950.

THOMAS F. MUlZPHY,

Assistant Oommz'ssioncr of Patents. 

